CX-5 Cylinder Deactivation-Deactivation

[GTXT23]

First - The system operates so flawlessly - its impossible to know when its " on " or not unless looking at the mpg or the display. I still would like to know what the procedure would be to program it off ?

I mean the cylinders dont stop moving / so a computer is cutting the fuel / can it be re-programmed to stop deactvating- ?
It cant be to much of a mystery with all the computer knowledge that exists -
I mean a laptop and software are the tools
?
Post warranty expiration of course .
Anyone here have experience in that area ?
thnx

 

[paris1]

First - The system operates so flawlessly - its impossible to know when its " on " or not unless looking at the mpg or the display. I still would like to know what the procedure would be to program it off ?

I mean the cylinders dont stop moving / so a computer is cutting the fuel / can it be re-programmed to stop deactvating- ?
It cant be to much of a mystery with all the computer knowledge that exists -
I mean a laptop and software are the tools
?
Post warranty expiration of course .
Anyone here have experience in that area ?
thnx

If it is as undetectable as you say (and I agree it is) why worry about how to defeat it?

 

[wlong01]

You would have to have high level knowledge of the ECM as well as the source code in order to start to understand the programming. That's a trade secret and probably not accessible unless you're a Mazda engineer. There's no menu selection to stop CD.

 

[GTXT23]

If it is as undetectable as you say (and I agree it is) why worry about how to defeat it?

Not worrying trust me -- Its an alteration I would only consider if it was simple and way way past warranty - like shutting of SCBS -

 

[stickerbush]

I don't see what's to be gained if it could be disabled, you would still have all the associated hardware including the head that is more prone to cracking.

 

[GTXT23]

I don't see what's to be gained if it could be disabled, you would still have all the associated hardware including the head that is more prone to cracking.

Its an exploratory question / not rhetorical-
Of all the Mzdas Ive owned and have in my collection the 2023 CX-5 and CX-5T are both quite special and I keep ALL examples in OE factory delivered condition -
Cracked cylinder heads is off topic and not relevant to a 2023 NA/ and the question - I refer you to 2020-2021 2.5T/NA cracked cylinder head threads - -
Zoom Zoom !
-Saraba Tomoyo

 

[yrwei52]

⋯
Cracked cylinder heads is off topic and not relevant to a 2023 NA/ and the question - I refer you to 2020-2021 2.5T/NA cracked cylinder head threads -

I wouldn’t be that optimistic as we still see cracked cylinder head report from time to time from the 2.5L NA with CD on newer CX-5 and other models.

It is still happening with the 2022 models. I just got my cylinder head replaced under warranty. It's a CX-5 with a skyactive engine; it's not the turbo. I bought it new in March of 2022 and it only has 13,000 miles on it. There were no warning signs or symptoms other than the low oil level light coming on. I have the oil changed twice a year, so that definitely shouldn't have happened. I stopped immediately so no damage was done to the engine. I hope the replacement head will last.

Not like the 2.5T, Mazda has never modified the cylinder head to the 2.5L NA with CD like they did to the 2.5T to fight against cracks. The cracked cylinder head will happen from time to time on the 2.5L NA with CD even on newer MYs although I believe it won’t be as frequent as the 2.5T. There’re several videos showing the cracked head, and plenty of reports here if you’re interested.

Cracked Cylinder Head with Oil leaking...How common is this? - 1

Cracked Cylinder Head with Oil leaking...How common is this? - 2

Cracked Cylinder Head with Oil leaking...How common is this? - 3

Regarding the topic,
The mechanic from the videos I posted before seems to be very experienced and he was literally shocked when he started welding the crack. The thickness of aluminum in that area was around 2mm. As an example, he was comparing and showing some Chinese brand cylinder head he found in his workshop, and the thickness of the aluminum edge there was about 7mm, which is approx 3,5 thicker.
Finally, he was highly disappointed with the way how Mazda designed the new cylinder head, specifically in saving the cost of aluminum in that area.
His advice was to not leave this particular engine downtime for a long period, as hydraulic cranks (the area where cracks appear)can possibly get jammed and cause significant stress when the engine is starting again after a long downtime.

And:

NA CX-5 with Cylinder Deactivation Engine Repairs - Report In

And do you aware there’s another potentially major problem on switchable hydraulic lash adjusters for cylinder deactivation? Although Mazda has modified this switchable HLAs to fix the tapping noise based on a Service Alert, unfortunately there’re reports that the tapping noise has returned after the revised switchable HLAs were installed.

CX-5 Tapping noise

Sad to report that the engine tapping noise has returned on my CX-5. Very disappointing. Almost time for an oil change (oil level shows about half way between the two holes in the dip stick) so I'm going to do that tomorrow or Saturday and see if that makes any difference (kinda doubting it). If not, I may have to take the car back into the dealer to have them check it out.


View attachment 322569

But I do believe disabling the cylinder deactivation should help preventing the head cracking. You reduced the drastic temperature changes on cylinder #1 and #4 which will reduce the uneven stress applied to the cylinder head in those areas.

Unfortunately there’s an aftermarket module available to disable Mazda’s annoying i-stop, but nothing available to disable Mazda’s cylinder deactivation at this time.

 

[ruthrj]

It would be cool if there was a way to trick the CD into not activating. Honda owners with the V6 (Odyssey, Ridgeline) can install aftermarket resistors on the line from a specific temperature sensor. It tricks the system into thinking the engine isn’t warm enough to deactivate the cylinders. I have no idea what the go/no-go conditions are for the Mazda design.

Long term effects of cylinder deactivation (which have not been reported here to be fair) could be oil consumption, piston ring wear, and increased wear to motor mounts. I think the Mazda line 4 design mitigates some of the additional wear and tear to motor mounts vs deactivation in something like Hondas V6.

An odd consequence I had not thought of was particulate emission levels. During deactivation particulate levels can increase, and now I’m starting to see reports of manufacturers adding gas particulate filters (think diesel style systems) to the emission control system.

 

[yrwei52]

⋯ An odd consequence I had not thought of was particulate emission levels. During deactivation particulate levels can increase, and now I’m starting to see reports of manufacturers adding gas particulate filters (think diesel style systems) to the emission control system.

Not to worry about those never-ending emission control add-ons as we all are going to drive EVs very soon!

 

[GTXT23]

Getting ready for a major road trip and I'm defaulting to the NA instead of the Turbo for mileage. The CD does a great job on long stretches. Last trip I got 35.2 mpg avg. at just about 900 miles.

Here are a few suggestions I am laying out there , because other issues were mentioned in some replys and the omission of all the facts relating to these things can be far more intrusive than the actual rarity of the things mentioned ..so

personal opinion based on lifetime ownership experience as well from a 30+ year mechanic/
Mazda master tech
:
When you drive , make sure the engine is fully warmed up before getting into any higher rpm driving -- and I dont mean that right when the coolant gauge goes to 209 + - , I mean that all operating parts from the top end down have reached temperature stasis - I know on break in the OM it says as soon as you get thru the initial warm-up ( once called automatic choke ) and the rpms have dropped to 8-9h rpm to drive. Thats for a seating process on parts , but does not mean drive it like mad- and it has a qualifier on that as well.
I say this because a common issue is hard driving while engine parts are at varying degrees of warm up, thus varying tolerances and you can potentially end up with all sorts of issues i.e. cracked heads etc. .
Keep your fluids correct, do regular spot checks on all systems and regular servicing ,check tire pressures ( when cold- on door - before driving ) and enjoy a long happy motoring experience with your Mazda-.... If you buy used- which is OK , "caveat emptor" there are many articles on used buying , and I read one recently on rentals which have low miles and good warranty but usually overall they are driven much harder and often abused- some issues dont arise until later on taxed systems or abused systems -- so be cautious !- I mention this because when in your life have you ever seen someone warm up a rent a car before driving it ?
--Zoom Zoom !

 

[yrwei52]

Checked with service writers in multiple locations whom I trust( and known for 30+ yrs ) prior to purchase and as well today- and there is not only no recall on any of those issues but the incident of any engine part cracking ( the cylinder head ) is isolated to a few cases that were found in a state of 35M people, another state close by had 2 ? -We are talking less than a fraction of of 1% of these engines --

Yes I also checked with the Master Tech and parts guy at my Mazda dealer and both of them admitted cracked cylinder head issue on both the 2.5L NA with CD and the 2.5T. In early days Mazda handled the case with the whole engine replacement and the replacement engines were back ordered for as long as 6 months! This’s in line with reports here in this forum on the wait time. Mazda eventually issued a TSB for the 2.5T and revised the cylinder head and exhaust manifold gasket to fight the head cracking on the 2.5T; and issued a Service Alert created a new part number on the replacement cylinder head with valves and rocker arms pre-installed for the 2.5L NA with CD to save the replacement labor time. And here:

I made an account just to reply to this thread. I've been a tech for Mazda for over 15 years now, doing my second bad head related replacement today actually. The first time I found one was on a CX9. No complaints, was just a simple 16k service and I noticed that the oil and coolant had mixed together, opened a ticket to Mazda Canada and they sent an engine replacement. Now the problem is so common that we just replace the head and gasket. The problem seems to be from a small crack in the head near the exhaust manifold bolts. The engine will either leak coolant or oil depending on where it's located, but the leak gets worse the hotter the engine gets. Thanks to supply problems, took well over 2 months to get the parts needed to repair this CX5 I'm working on today. As far as how common this is, my dealership has done maybe 9 or 10 heads in the last year.

We never remove the engine, requires the subframe to come down and a LOT more work afterwards including an alignment. I'm also not sure how you could do this job without removing the timing chain altogether, because both cams come out during the head replacement and the actual timing chain cover is bolted in some places to the head. The job is a messy pain in the rear, and warranty pays next to nothing compared to CP. But right now during slow season we welcome this sort of work. Just a shame it's happening, but luckily every single repair we have done has been covered by Mazda with the customer in a rental. Sometimes for weeks or months.

The 2.5NA and 2.5T are the backbone of the Mazda corporation- - literally and if there was a major flaw they would already be bankrupt -- Not saying things dont occur- As humans are imperfect thus everything we make is also imperfect ,but to anyone that it has - I can only say I would be glad that Its Mazda as they will right it - I think that some people have a bad experience and they blow it out of proportion and try to ruin others ownership experience without giving ALL the data -- Its simply highly highly unlikely and rare . Thats the truth-

The cracked cylinder head issue on the 2.5L NA with CD may be rare percentage wise, but it does happen from time to time. Nobody knows if or when his / her 2.5L NA with CD would develop the crack on the cylinder head. If one unfortunately encountered this problem, it’d cost him / her an arm and a leg to fix it if there’s no warranty.

Just for the comparison, we’ve seen at least 10 reports here including a 2022 CX-5 for the crack head on the 2.5L NA with CD, but we have never seen even one incident of cracked cylinder head reported here on the 2.5L NA without cylinder deactivation where the engine is older and having higher mileage!

 

[GTXT23]

If it is as undetectable as you say (and I agree it is) why worry about how to defeat it?

- These are questions if you re-read it . The subject arises greatly about the CD system , thus many people might be asking the same questions- I like it ( as I said at the opening of the post ) and wouldnt even consider changing anything on the vehicle with regards to the OE set up, unless its an accepted practice and approved by Mazda- I suggest the same to everyone else as well -- I do like some aftermarket floor mats , tires are open to suggestions , things like that - no issue switching .

 

[GTXT23]

Yes I also checked with the Master Tech and parts guy at my Mazda dealer and both of them admitted cracked cylinder head issue on both the 2.5L NA with CD and the 2.5T. In early days Mazda handled the case with the whole engine replacement and the replacement engines were back ordered for as long as 6 months! This’s in line with reports here in this forum on the wait time. Mazda eventually issued a TSB for the 2.5T and revised the cylinder head and exhaust manifold gasket to fight the head cracking on the 2.5T; and issued a Service Alert created a new part number on the replacement cylinder head with valves and rocker arms pre-installed for the 2.5L NA with CD to save the replacement labor time. And here:







The cracked cylinder head issue on the 2.5L NA with CD may be rare percentage wise, but it does happen from time to time. Nobody knows if or when his / her 2.5L NA with CD would develop the crack on the cylinder head. If one unfortunately encountered this problem, it’d cost him / her an arm and a leg to fix it if there’s no warranty.

Just for the comparison, we’ve seen at least 10 reports here including a 2022 CX-5 for the crack head on the 2.5L NA with CD, but we have never seen even one incident of cracked cylinder head reported here on the 2.5L NA without cylinder deactivation where the engine is older and having higher mileage!

 

[ctbale]

The comments about the Honda V6 are dead on. Honda V6 owners have been tricking their engine computer into not activating CD for years and years. I guess my first question is why Mazda why. This is a 4 cylinder... this is an amazing engine.... why did you bastardize it with this system that can't possibly add more than one MPG. I'm a long time mechanic and it's no secret that CD only helps the cafe numbers. Doesn't help your engine. I almost bought a 2022 CX-5. But at the last minute I found out about the CD on this motor. Kind of shocked me. I won't own an engine with CD. So I looked at the turbos but by the time I got over 40,000 I went to the other side of the lot and pick me up a new 22 CX-9 without CD for 36. Updated head so fingers crossed. I almost bought a ford 150 a couple years ago with the 5.0 l but found out that engine also has CD now. First year 2021 I believe. The ford guys are using a tuner that you plug into the OBD2 connector to defeat CD with success. I doubt there's enough interest in defeating the Mazda CX-5 CD for that type of technology. Besides Ford owners really are used to working on their vehicles. Haha.

 

[ctbale]

There is the issue of the cracked head on CD but the bigger issue that effects EVERY SINGLE NA CD is the same issue the v6 honda folks are dealing with is what its doing to their back 3 cylinders. The CD is causing many to have to redue the back three CD cylinders and pistons due to high oil consumption and low compression. This is documented on many many of these motors starting at 100k. Why Mazda why????? Why did you do this to an extremely fuel efficient 4 cylinder? Shame

 

[yrwei52]

I almost bought a 2022 CX-5. But at the last minute I found out about the CD on this motor. Kind of shocked me. I won't own an engine with CD.

Same here. I won't own an engine with cylinder deactivation. And I almost bought a 2018 CX-5, that’s the MY Mazda “secretly” and suddenly introduced the cylinder deactivation to its solid 2.5L NA without any prior announcement and advertisement.

The long term side effects on cylinder deactivation are obvious and proven due to the drastic temperature changes on cylinders with activation and deactivation. Not to mention the pistons need extra energy to move compressing and decompressing the air in these sealed cylinders when they’re “activated”. OP’s idea is solid to disable this feature but unfortunately there’s nothing available for Mazda’s CD at this time. And those switchable hydraulic lash adjusters used by CD even with updated version are still having failures reported.

 

[GTXT23]

On a more serious note - It seems " we " aka- Mazda owners , are indeed a different breed of car buyer than others- Mazda takes risks that others dont or failed at - so we must like that ?
, the prime example being the 47 Ronin hired by Mazda to do nothing but make the rotary engine succeed - and we know that story leading up to 1991 Le Mans. As well Mazda sticking with traditional drivetrains with skyactive in 2013- no hybrids or electric stuff - well til now -
We definitly watch and maintain our vehicles at a closer level - They know this.

Its clear theres a sore spot on a fractional number of 2.5 powerplants having craked heads - If it was mine - heck yes !
-Regardless of how rare or not It begs the question - how did it occur ? Since the subject seemed to drive itself in that direction- I called a few " experts " me not being an engineer - and Mazda has dedicated people who do nothing but investigate and report on these things so that " constant improvment " is made -
It seems theres a process of elimination instead of just looking for whats wrong ...eliminating whats not or is right as well - My original question was predicated on this - Madza stealing 1st place in reliabiliy from Toyota and their 2.5-na+t being the premiere power plants - keeps a close eye on any issues. Theres been speculation in here that CD is the cause of these cracked heads - yet there is not one single shred of physical evidence the point to that . Thus if so , Mazda could in quick time have a recall and literally have every 2.5na's CD disabled - and that has not occured . If its CD why did it occur on turbos ?
Mazda did makes physical changes to the head and I nor those I spoke with gave me other information, except that as of now theres 0 evidence that its Cd which caused these extremely rare occurences.
Thus it continues to be employed.
We do Mazda a great service here by being watchdogs and collaborating- they definitly read this forum - that said , Its my hope we continually look for soild evidence when posting new information. As well hope that everyones experince is great and those that need help ( like me ) get good solid fact / experience based information we can rely on. I think the people here are exceptional and a few beyond - like the poster Y-52
Thank you for all the great photos and links it helps greatly.

 

[ctbale]

I haven't followed the 2.5 NA CD engine that close. The way more common cracked head on the turbo, I do have my theory. I think when Mazda was doing the consideration for a generation change on the CX-9 they came to a y in the road. They could either hastily develop a larger power plant from scratch or boost the venerable 2.5. seems like an obvious choice and one I don't disagree with. Many other car manufacturers have turboed 2.5S. but I would have rather seen a 6 cylinder in the CX-9 in 2016. I think the cracked heads on the 2.5t is occurring because of the extra weight and heat torsion on those six 8mm studs that weren't there before. Simple as that. The fact that they came up with an improved exhaust gasket as well as an improved head for the fix kind of tells me that's the problem.

 

[GTXT23]

I haven't followed the 2.5 NA CD engine that close. The way more common cracked head on the turbo, I do have my theory. I think when Mazda was doing the consideration for a generation change on the CX-9 they came to a y in the road. They could either hastily develop a larger power plant from scratch or boost the venerable 2.5. seems like an obvious choice and one I don't disagree with. Many other car manufacturers have turboed 2.5S. but I would have rather seen a 6 cylinder in the CX-9 in 2016. I think the cracked heads on the 2.5t is occurring because of the extra weight and heat torsion on those six 8mm studs that weren't there before. Simple as that. The fact that they came up with an improved exhaust gasket as well as an improved head for the fix kind of tells me that's the problem.

I totally agree -- that 9 should have had a new - super high torque / supercharged . inline 6 - it would have made a bigger difference all around -- sales , power etc --- Now Mazdas got a 6 going into the 90 ? I hope Mazda dosent go down the Subaru road ......Sub tried a 6 that was a 3.0 and it was a dog